Piseinotecus is a genus of sea slugs, aeolid nudibranchs, marine gastropod mollusks in the family Piseinotecidae.Korshunova T.; Fletcher K.; Martynov A. (2025). The endless forms are the most differentiated—how taxonomic pseudo-optimization masked natural diversity and evolution: the nudibranch case Zoological Journal of the Linnean Society. Volume 204, Issue 4, August 2025.Cervera J.L., García J.C & García F.J. (1987). Una nueva especie de Piseinotecus Marcus, 1955 del litoral ibérico. Bollettino Malacologico 22(9-12): 215-222
Etymology The name Piseinotecus comes from the Portuguese sentence "pisei no Teco" (I stepped onto Teco). Teco was the name of a dog of the zoologists Ernst Marcus and Eveline Du Bois-Reymond Marcus. While they were looking for a name for the genus, their friend, the zoologist Diva Diniz Corrêa, was visiting them and stated the sentence while coming down the stairs to announce that she had accidentally stepped onto their dog.
Species Species in the genus Piseinotecus currently include: Piseinotecus divae Er. Marcus, 1955 Piseinotecus ernestina Ortea & Moro, 2020 Piseinotecus gonja Edmunds, 1970Edmunds, M. 1970. Opisthobranchiate Mollusca from Tanzania. II. Eolidacea (Cuthonidae, Piseinotecidae and Facelinidae). Proceedings of the Malacological Society of London 39:15-57. Piseinotecus gonja kima Edmunds, 1970MolluscaBase eds. (2026). MolluscaBase. Piseinotecus gonja kima Edmunds, 1970. Accessed through: World Register of Marine Species on 2026-05-31.. Piseinotecus minipapilla Edmunds, 2015 Piseinotecus sphaeriferus (Schmekel, 1965)
Ekimova et al. (2026) posits Piseinotecus soussi should be included herein Ekimova I., Carmona L., Mikhlina AL., Grishina D., Stanovova M.V., Schepetov D.M., Hoover C., de Souza-Canal J., Kuznetsov K.O., Valdés A.; (2026). Neither "lumpers" nor "splitters": A global revision of Flabellinidae s.l. nudibranchs (Gastropoda: Heterobranchia: Nudibranchia). PLoS One 21(5): e0347759.. Korshunova et al. (2025) provided robust evidence for its current designation of Phetia soussi under family Unidentiidae.
Species brought into synonymyMolluscaBase eds. (2026). MolluscaBase. Piseinotecus Er. Marcus, 1955. Accessed through: World Register of Marine Species on 2026-05-31. Piseinotecus evelinae Schmekel, 1980: synonym of Flabellina gabinierei (Vicente, 1975) Piseinotecus gabinierei (Vicente, 1975): synonym of Flabellina gabinierei (Vicente, 1975) Piseinotecus gaditanus Cervera, García-Gómez & García, 1987: synonym of Flabellina gaditana (Cervera, García-Gómez & F. J. García, 1987)
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